Leaders of the national parks which make up the lion’s share of Prime Minister’s constituency have issued an extraordinary appeal directly to Rishi Sunak, saying his Government’s plan to relax planning rules in protected areas would cause “irreparable and substantial harm”.

In a joint letter to Mr Sunak, Yorkshire Dales and North York Moors national park chairmen Neil Heseltine and Jim Bailey said allowing many hundreds of buildings such as barns, cafes and offices to be converted into housing without planning consent could cause “a wide range of harmful and permanent impacts” to Richmond constituency.

There are an estimated 6,200 traditional farm buildings in the Yorkshire Dales alone, and the stone field barns or cowhouses have been a particularly protected feature of areas like Swaledale and Wensleydale.

Darlington and Stockton Times: Low lying fog in Wensleydale, pictured on a trip to Carperby by Angela Baker

The unprecedented appeal follows Government officials underlining there would need to be “watertight reasons” given in a consultation over its Levelling Up Bill proposals to abandon the legislative move which is aimed at speeding up housebuilding.

It also follows Mr Sunak drawing widespread criticism from climate change campaigners for announcing a series of U-turns on national climate change targets and hailing the approval of a major environmentally damaging fossil fuel project in the North Sea.

Justifying the proposals, the Government said granting permitted development rights on an array of properties in protected areas would provide certainty for people wanting to develop homes and remove time and financial barriers in submitting a planning application.

While some Conservatives in the county have privately voiced partial support for the proposals, many other people believe they would be disastrous for the protected landscapes.

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The chairmen told Mr Sunak they had “grave concerns” as the changes could see sensitive landscapes littered with many more second homes and holiday lets, a factor cited as the primary threat to communities in the parks. 

The letter states: “These changes, in our view, will cause huge damage to nationally protected landscapes and their economies whilst being counterproductive to many of the Government’s own policy goals for healthy rural communities.

“People will rightly ask why, in an area with national protection for its natural beauty, planning permission is needed for minor developments such as a domestic side extension or a porch over a certain size and yet an agricultural business is able to develop up to ten houses in the open countryside without needing to apply for planning permission.”

They said the move would be “deeply unpopular” and bring the planning system into disrepute with a further loss of public confidence.

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The letter adds: “The impact on walking in the valleys of Upper Swaledale and across the Cleveland Hills to the Esk Valley, the route of the iconic

Coast to Coast Walk should these proposals be enacted, doesn’t bear thinking about.

“New conversions will bring new power lines, roads, domestic gardens, additional lighting, play equipment and other residential paraphernalia into otherwise traditional pastoral landscapes, which Parliament has committed to protect for the nation as places of great natural beauty.”

The chairmen wrote that, in the absence of planning rules, it was inevitable the market would dictate a building’s use, with most, if not all, of the conversions ending up as second or holiday homes, meaning they would be beyond the reach of most local people.

The letter states relaxing planning rules would be likely to lead to an accelerated loss of local services in villages, with buildings converted into yet more second or holiday homes.

A spokesman for Mr Sunak declined to comment when asked about the national parks’ claim that the changes would be profoundly damaging to his own constituency.

A Department for Levelling Up, Housing and Communities spokesperson said: “Our public consultation has closed and we will now consider all responses before setting out next steps.

“We have been clear that any developments must be considered sympathetic to the surroundings, enhance the environment and meet the needs of people in the local community.”

North Yorkshire Council’s Independent group leader, Richmond councillor Stuart Parsons, said Mr Sunak appeared not to understand the rural economy.

He said: “Rishi Sunak is basically talking about the extinction of national parks with what he and his Government wants to allow.

“This will not improve the rural economy and by abdicating responsibility to respond to a letter addressed to him he is showing he is a coward and doesn’t understand his own Government’s policies. With a forthcoming General Election the backlash will be rapid.”